Mac OS X v10.10 is out for beta testing please do not use this pre-release software in a production environment that contains important data. You should back up all of your data before installing this OS version and regularly back up data while using the software. If by any chance the installation of OS X v10.10 Developer Preview 1 fails, try using Disk Utility from a Recovery HD to repair the disk.

Developer Preview System Requirements

The OS X v10.10 Developer Preview supports the following Macs:

iMac (Mid 2007 or newer)

MacBook Air (Late 2008 or newer)

MacBook (Late 2008 Aluminum, or Early 2009 or newer)

Mac mini (Early 2009 or newer)

MacBook Pro (Mid/Late 2007 or newer)

Mac Pro (Early 2008 or newer)

Xserve (Early 2009)

Known Issues

Migration Assistant may hang while transferring your information from a Time Machine backup. To proceed with the login, quit the Installer.

Developer Preview 1 may be unable to install over an encrypted volume.

The system may appear to hang if the Login password does not match the OpenDirectory or keychain password. Pressing the Esc key will allow the login to proceed.

Calendar

Known Issue

Some all day events may not be displayed. Navigating to a different day, and back will display the missing events.

Continuity

Known Issues

Some apps that use Handoff will mistakenly show as Safari in the iOS lock screen and OS X Dock.

In some cases, not all devices associated with an Apple ID will pair successfully. These devices will be unable to use Handoff, Phone calls, or Instant HotSpot.

When using a Mac, Handoff may sometimes stop showing icons on other iOS and OS X devices.

Handoff-based Bluetooth connections between devices may stop working after trying to use Handoff.

In some cases, using Handoff with Safari will result in an old URL being resumed instead of the current URL.

Phone calls to and from the Mac may sometimes not complete or send and receive audio.

Dictation

Known Issues

Dictation shortcut text field is missing from Dictation preferences.

Opening the Customize Commands of the Dictation preference panel may cause System Preferences to hang.

Family Sharing

Known Issues

Items already owned by family members must be re-downloaded from the Purchased page (not Store pages) to get them free of additional charge.

Email invitations are not enabled; members can join using push notifications or via inline password entry flow.

You can’t approve an “Ask to Buy” request from the requestor’s iOS device.

Streaming video from iCloud may present a black screen. Downloading the video will allow playback.

Finder

Known Issue

Some graphical corruption may be visible when using Icon View in Finder.

iCloud

Notes

iCloud Documents & Data created with Developer Preview 1 will be deleted from the servers at some point during the beta period. Your devices using Developer Preview 1 will maintain copies of those deleted iCloud Documents & Data. After the server deletes that data, all iCloud Documents & Data you previously used on OS X v10.9 and earlier or iOS 7 and earlier will be copied on the server over to the OS X v10.10/iOS 8 version of iCloud Documents & Data. Your devices using Developer Preview 1 will then re-upload their copies to the servers. If you delete those copies on your Mac before they are uploaded to the servers, and if you don’t have a backup of them, those documents will be lost. Documents and data managed on earlier releases of OS X and iOS will not be affected by any of this.

The Web UI for managing iCloud Documents & Data does not show the documents and data managed by systems running Developer Preview 1. Documents and data synced with previous operating systems will be displayed.

Changes to iCloud Documents & Data in Pages, Numbers, and Keynote on Macs using OS X v10.10 Developer Preview are only available on other devices using OS X v10.10 Developer Preview or iOS 8.0 beta. Any changes from devices using earlier versions of OS X or iOS will not be available. Changes will also not be visible in Pages, Numbers, and Keynote on iCloud.com.

Known Issues

Some account password prompts may request the same login information several times before dismissing.

Finder may spin after adding a large number of items to iCloud Drive.

iPhoto

Known Issues

iCloud settings for My Photo Stream and Shared Streams will be preserved from earlier versions of OS X on upgrade to Developer Preview 1. However, turning off Shared Streams will turn off My Photo Stream, and visa versa.

Turning off My Photo Stream or Shared Streams may not be available in System or Application preferences after upgrading to Developer Preview 1.

Mail

Known Issue

Mail may not be able to set up new Mail accounts within the Mail application.

Server

Known Issues

Systems running Developer Preview 1 may be unable to connect to share points over SMB.

Systems with earlier versions of OS X may not be able to connect to a server running Developer Preview 1 over SSL.

Tools

Notes

In Developer Preview 1 unsigned or improperly signed kexts will not be loaded. To use unsigned kexts during development, this strict check can be disabled by adding a “kext-dev-mode=1” boot arg.

AVFoundation changes the way some ID3 metadata values are represented as AVMetadataItems for binaries that are linked with the Developer Preview 1 SDK.

Known Issues

In some cases, multi-word script terminology is not properly mapped to JavaScript identifiers by the runtime, and so the properties supported in the runtime do not always match the properties that are documented.

Installing kernel extensions on systems running Developer Preview 1 may make your system un-bootable. To fix the issue, boot into the Recovery Partition and run the following:

touch /Volumes/<10.10 Partition>/System/Library/Extensions

kextcache -u /Volumes/<10.10 Partition>

Some Apple Script Editor toolbar buttons may not enable/disable properly. The menu items can be used instead.

When running JavaScript in the script editor, Boolean evaluations may fail on second execution.

Other

Known Issues

Some text may not be localized to the selected system language.

Some panels may appear transparent.

Applications that are not compatible with Developer Preview 1 may hang before presenting an incorrect error.

Some 64-bit preference panels may fail to load after restarting System Preferences in 64-bit mode. Relaunching System Preferences resolves the issue.

Netboot may fail to find local drives and shutdown.

Systems without a display attached may experience decreased performance.

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